Articulated ski boots having upper and lower members pivotally connected together at a hinge-type joint substantially in the region of the ankle of the user have been proposed to allow increasing skiing flexibility since they permit adjustment of the angle at which the cuff holds the inferior or distal extremity of the leg relative to the ski to which the lower member is secured.
The boot generally comprises a casing formed from the two enclosures previously described, which can be relatively rigid shells and a lining which can be applied to a sock and/or can be previously fitted into the casing part and composed of a relatively thick, yieldable, formfitting and flexible material, e.g. a synthetic-resin foam.
The locking means for securing the cuff at a predetermined orientation to the lower casing member or sole piece of the boot is generally provided along the rear thereof in the region (spine) of the boot paralleling the Achilles tendon of the skier and may be adjustable and/or releasable.
Swiss Pat. No. 518,071, for example, shows a ski boot of which the latter locking device is of a particularly simple type since it is constituted basically by a metal tongue rigid with the upper member of the cuff of the boot and presenting a lug adapted to be introduced into a receiving element fixed to the lower member or sole piece of the boot.
The lug or projection can engage any one of a number of seats provided at different levels and adapted to be locked selectively at these levels to secure the upper member of the boot at a particular selected angle with respect to the lower member.
A somewhat more complex configuration has been shown in Swiss Pat. No. 512,204. Here the locking device comprises a piston assembly coupling the upper and lower parts of the boot and in which the friction stroke is limited by an adjustable means.
Still another arrangement for bracing the cuff or upper member with respect to the sole piece or lower member of the boot casing is found in Swiss Pat. No. 519,970, in which the lower tongue projects upwardly into a flat socket of the upper member receiving said tongue and the two are locked together by a bail passing through holes or bores of the tongue.
Swiss Pat. No. 623,209 abuts a mechanism on the upper member against a portion of the ski binding or latches the upper member relative to the lower member by a latching mechanism swingable about the pivot between the upper and lower casing member and braced, in turn, upon a portion of the binding.
In Swiss Pat. No. 611,496, mechanisms are described for adjusting the location of the pivot and include a tension member reaching toward the back of the ski boot.
In French Pat. No. 1,472,863 another tension system reaching below the boot has been shown, this arrangement utilizing an elastic band connecting the cuff with the sole portion of the ski.
French Published Application No. 2,491,304 describes a tongue and socket connection between the pivotal upper member and still another member of the cuff.
German Open Application No. 1,805,251 provides a ratchet arrangement in which a pivotal pawl has a tooth which engages in teeth provided in the lower member and braced against the upper member or connected thereto.
The ski boot of the published PCT application corresponding to the International Publication No. WO 81 01644, in which U.S. Pat. No. 3,561,139 was cited, describes a ski boot in which the cuff assembly is coupled to the lower shell member by an adjustably located pivot utilizing various slot configurations.
From the foregoing summary of the state of the art known to applicant at the time this invention was made, it should be apparent that a wide variety of mechanisms has been proposed for adjusting the orientation of the cuff or upper shell member on the lower shell member or sole piece of the boot.
These mechanisms can be divided basically into a small number of categories. In the first category are those which adjust the position of the pivot. These systems have the disadvantage that they cannot always effectively brace the cuff member with respect to the lower shell member in a fixed position of a pivot, so that the skier must either be uncomfortable or must readjust his boot in an inconvenient way.
A second group utilizes bracing systems for the upper cuff member which depend upon the binding and are particularly prone to problems arising from the accumulation of snow on the binding.
A third group utilizes catches and releases on the back or underside of the boot of a type which requires these releases to be exposed to the elements and to therefore become packed with snow and ice to make their use difficult.
Finally, there are systems which, although apparently simple, do not permit setting of the angle satisfactorily.